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<a href="cong__ctl__classic_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="detail_2net__flow__fwd_8hpp.html">flow/net_flow/detail/net_flow_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="preprocessor">#include &quot;<a class="code" href="cong__ctl_8hpp.html">flow/net_flow/detail/cong_ctl.hpp</a>&quot;</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="preprocessor">#include &quot;<a class="code" href="cong__ctl__util_8hpp.html">flow/net_flow/detail/cong_ctl/cong_ctl_util.hpp</a>&quot;</span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span> </div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1net__flow.html">flow::net_flow</a></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span>{</div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="comment"></span> </div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment">/**</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"> * Classic congestion control, based on Reno (TCP RFC 5681), with congestion avoidance, slow start,</span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment"> * and congestion window halving (etc.) upon a loss event.  Implements Congestion_control_strategy</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> * abstract API.</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> *</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> * The basic idea is: start with a narrow pipe.  With each acknowledgment, grow the width of the</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> * pipe exponentially (a/k/a &quot;slow start&quot;).  Eventually this will either hit the maximum width or</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> * cause loss. Once loss is detected, guess that the &quot;steady-state&quot; pipe width is about half of that</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> * at the point where loss occurred, set the pipe to that width and increase the pipe width but</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> * slowly (linearly) as acknowledgments arrive (a/k/a &quot;congestion avoidance&quot;).  Eventually this</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> * will cause loss again: again guess pipe is half that width and start at that width and increase</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> * linearly (congestion avoidance again).  Continue indefinitely.  This results in the</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> * characteristic CWND vs. time graph, where CWND first explodes up, then goes up diagonally and</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> * vertically down, up, down, up, down, like a saw edge.</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> *</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> * Additionally, on major loss (Drop Timeout), guess the steady state pipe width as above but reset</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> * the actual pipe width to its narrowest value.  This will cause exponential growth again until the</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> * steady state pipe width is reached, then linear growth.</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment"> *</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> * On idle timeout (when connection is seen as idle in the send direction), reset the pipe to its</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> * original narrow width but make no change to the steady-state pipe width.</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> *</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> * The strength of this algorithm is that it&#39;s time-tested and saved the Internet from collapsing.</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> * The weakness is that once it encounters loss -- which may well be random loss and not a sign of</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> * congestion -- it backs off very conservatively (half).  This means in a somewhat lossy</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> * environment one flow like this will fail to take advantage of the available bandwidth.</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> *</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> * @note The above refers to &quot;half&quot; the pipe width being used when backing off due to loss, as in classic Reno,</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> *       but actually we make it configurable through socket options.</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> *</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span><span class="comment"> * @see Congestion_control_classic_with_bandwidth_est that acts similarly but instead of backing</span></div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment"> *      off conservatively to half (etc.) the pipe, backs off to an estimate as to the available</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment"> *      pipe width based on a bandwidth estimator.</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> */</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic.html">   63</a></span><span class="keyword">class </span><a class="code hl_class" href="classflow_1_1net__flow_1_1Congestion__control__classic.html">Congestion_control_classic</a> :</div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span>  <span class="keyword">public</span> <a class="code hl_class" href="classflow_1_1net__flow_1_1Congestion__control__strategy.html">Congestion_control_strategy</a></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span>{</div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="keyword">public</span>:</div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span>  <span class="comment">// Constructors/destructor.</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment"></span> </div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment">   * Constructs object by setting up logging and saving a pointer to the containing Peer_socket.</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment">   * Congestion window is chosen to be some small initial value, and an exponential congestion</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment">   * window growth is set up to continue indefinitely, until a loss event, drop timeout, or idle</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment">   * timeout.</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment">   *</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment">   * Only a weak pointer of `sock` is stored: the `shared_ptr` itself is not saved, so the reference</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment">   * count of `sock` does not increase.  This avoids a circular `shared_ptr` situation that would arise</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment">   * from `*this` pointing to `sock`, and `sock` pointing to `*this` (the two objects *do* need access</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment">   * to each other, as explained in class Congestion_control_strategy doc header).</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment">   *</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment">   * @param logger_ptr</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment">   *        The Logger implementation to use subsequently.</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment">   * @param sock</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment">   *        The Peer_socket for which this module will control congestion policy.</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment">   */</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span>  <span class="keyword">explicit</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#aa4fd5c14f20d7534db287c78387d5f0e">Congestion_control_classic</a>(<a class="code hl_class" href="classflow_1_1log_1_1Logger.html">log::Logger</a>* logger_ptr, <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock);</div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span> </div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"></span> </div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment">   * Implements Congestion_control_strategy::congestion_window_bytes() API.</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment">   * @return See Congestion_control_strategy::congestion_window_bytes().</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment">   */</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span>  <span class="keywordtype">size_t</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a98ee7d39ccbacacaec6b9e0deff1e6b1">congestion_window_bytes</a>() <span class="keyword">const override</span>;</div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment"></span> </div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment">   * Implements Congestion_control_strategy::on_acks() API.  Congestion window grows either linearly</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment">   * (in congestion avoidance mode) or exponentially (in slow start mode).  There is no congestion</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment">   * avoidance mode until at least one of on_loss_event() or on_drop_timeout() occurs; at least</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment">   * until then slow start is in effect.</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment">   *</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment">   * Additional Peer_socket state used: none.</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment">   *</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment">   * @param bytes</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment">   *        See Congestion_control_strategy::on_acks().</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment">   * @param packets</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment">   *        See Congestion_control_strategy::on_acks().</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment">   */</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a34b8ef88093f082df7a935bbebfae2f3">on_acks</a>(<span class="keywordtype">size_t</span> bytes, <span class="keywordtype">size_t</span> packets) <span class="keyword">override</span>;</div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"></span> </div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment">   * Implements Congestion_control_strategy::on_loss_event() API.  Congestion window changes to some</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment">   * configurable constant fraction (like half) of its current value, and the next slow start (if</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment">   * any, e.g., on a later Drop Timeout) will end once the congestion window exceeds this value.</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment">   * Thus after this call congestion avoidance mode begins anew.</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment">   *</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment">   * Additional Peer_socket state used: Peer_socket::m_snd_flying_bytes (the # of bytes still In-flight</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment">   * after the loss event).</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment">   *</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment">   * @param bytes</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment">   *        See Congestion_control_strategy::on_loss_event().</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment">   * @param packets</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment">   *        See Congestion_control_strategy::on_loss_event().</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment">   */</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#af2340e68dbdbb8d6065ae487b05074be">on_loss_event</a>(<span class="keywordtype">size_t</span> bytes, <span class="keywordtype">size_t</span> packets) <span class="keyword">override</span>;</div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"></span> </div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment">   * Implements Congestion_control_strategy::on_drop_timeout() API.  Congestion window is set to a</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment">   * low value, while the next slow start session is set to end at roughly half (or some</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment">   * configurable constant fraction) of the current (pre-decrease) congestion window.  Thus a slow</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment">   * start session begins.</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment">   *</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment">   * Additional Peer_socket state used: Peer_socket::m_snd_flying_bytes (the # of bytes still In-flight</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment">   * after the loss event implied by the timeout).</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment">   *</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment">   * @param bytes</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment">   *        See Congestion_control_strategy::on_drop_timeout().</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="comment">   * @param packets</span></div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="comment">   *        See Congestion_control_strategy::on_drop_timeout().</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment">   */</span></div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a59148ce4dafea4063b6992b9670909dc">on_drop_timeout</a>(<span class="keywordtype">size_t</span> bytes, <span class="keywordtype">size_t</span> packets) <span class="keyword">override</span>;</div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="comment"></span> </div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="comment">   * Implements Congestion_control_strategy::on_idle_timeout() API.  Congestion window is set to a</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment">   * low value.  Thus a slow start session begins.</span></div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="comment">   *</span></div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span><span class="comment">   * Additional Peer_socket state used: none.</span></div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment">   */</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a588baa530b660a3437d3a39d68b16404">on_idle_timeout</a>() <span class="keyword">override</span>;</div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span> </div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="keyword">private</span>:</div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment"></span> </div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment">   * Returns the decay (as a percentage) to apply to the congestion window upon encounterling loss.</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span><span class="comment">   * RFC 5681-3.2.1 and formula (4) say this should 50 (i.e., halve it); but we make it configurable</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment">   * by a socket option.</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment">   *</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment">   * @return A percentage in the range [1, 100].</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment">   */</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span>  <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a6267f980c8a0f33f8213e1fa4b83ee16">congestion_window_decay</a>() <span class="keyword">const</span>;</div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span> </div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span>  <span class="comment">// Data.</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment"></span> </div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="comment">  /// The Reno CWND/SSTHRESH-changing engine and CWND/SSTHRESH storage.</span></div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a03a5671f57a7a8f7b0cdce200d29bd3b">  165</a></span><span class="comment"></span>  <a class="code hl_class" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html">Congestion_control_classic_data</a> <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a03a5671f57a7a8f7b0cdce200d29bd3b">m_classic_data</a>;</div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span>}; <span class="comment">// class Congestion_control_classic</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span> </div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span>} <span class="comment">// namespace flow::net_flow</span></div>
<div class="ttc" id="aclassflow_1_1log_1_1Logger_html"><div class="ttname"><a href="classflow_1_1log_1_1Logger.html">flow::log::Logger</a></div><div class="ttdoc">Interface that the user should implement, passing the implementing Logger into logging classes (Flow'...</div><div class="ttdef"><b>Definition:</b> <a href="log_8hpp_source.html#l01280">log.hpp:1284</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html">flow::net_flow::Congestion_control_classic_data</a></div><div class="ttdoc">Utility class for use by Congestion_control_strategy implementations that implements congestion windo...</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8hpp_source.html#l00076">cong_ctl_util.hpp:79</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html">flow::net_flow::Congestion_control_classic</a></div><div class="ttdoc">Classic congestion control, based on Reno (TCP RFC 5681), with congestion avoidance,...</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8hpp_source.html#l00063">cong_ctl_classic.hpp:65</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html_a03a5671f57a7a8f7b0cdce200d29bd3b"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a03a5671f57a7a8f7b0cdce200d29bd3b">flow::net_flow::Congestion_control_classic::m_classic_data</a></div><div class="ttdeci">Congestion_control_classic_data m_classic_data</div><div class="ttdoc">The Reno CWND/SSTHRESH-changing engine and CWND/SSTHRESH storage.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8hpp_source.html#l00165">cong_ctl_classic.hpp:165</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html_a34b8ef88093f082df7a935bbebfae2f3"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a34b8ef88093f082df7a935bbebfae2f3">flow::net_flow::Congestion_control_classic::on_acks</a></div><div class="ttdeci">void on_acks(size_t bytes, size_t packets) override</div><div class="ttdoc">Implements Congestion_control_strategy::on_acks() API.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8cpp_source.html#l00038">cong_ctl_classic.cpp:38</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html_a588baa530b660a3437d3a39d68b16404"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a588baa530b660a3437d3a39d68b16404">flow::net_flow::Congestion_control_classic::on_idle_timeout</a></div><div class="ttdeci">void on_idle_timeout() override</div><div class="ttdoc">Implements Congestion_control_strategy::on_idle_timeout() API.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8cpp_source.html#l00176">cong_ctl_classic.cpp:176</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html_a59148ce4dafea4063b6992b9670909dc"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a59148ce4dafea4063b6992b9670909dc">flow::net_flow::Congestion_control_classic::on_drop_timeout</a></div><div class="ttdeci">void on_drop_timeout(size_t bytes, size_t packets) override</div><div class="ttdoc">Implements Congestion_control_strategy::on_drop_timeout() API.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8cpp_source.html#l00126">cong_ctl_classic.cpp:126</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html_a6267f980c8a0f33f8213e1fa4b83ee16"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a6267f980c8a0f33f8213e1fa4b83ee16">flow::net_flow::Congestion_control_classic::congestion_window_decay</a></div><div class="ttdeci">unsigned int congestion_window_decay() const</div><div class="ttdoc">Returns the decay (as a percentage) to apply to the congestion window upon encounterling loss.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8cpp_source.html#l00164">cong_ctl_classic.cpp:164</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html_a98ee7d39ccbacacaec6b9e0deff1e6b1"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html#a98ee7d39ccbacacaec6b9e0deff1e6b1">flow::net_flow::Congestion_control_classic::congestion_window_bytes</a></div><div class="ttdeci">size_t congestion_window_bytes() const override</div><div class="ttdoc">Implements Congestion_control_strategy::congestion_window_bytes() API.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8cpp_source.html#l00033">cong_ctl_classic.cpp:33</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html_aa4fd5c14f20d7534db287c78387d5f0e"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html#aa4fd5c14f20d7534db287c78387d5f0e">flow::net_flow::Congestion_control_classic::Congestion_control_classic</a></div><div class="ttdeci">Congestion_control_classic(log::Logger *logger_ptr, Peer_socket::Const_ptr sock)</div><div class="ttdoc">Constructs object by setting up logging and saving a pointer to the containing Peer_socket.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8cpp_source.html#l00025">cong_ctl_classic.cpp:25</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic_html_af2340e68dbdbb8d6065ae487b05074be"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic.html#af2340e68dbdbb8d6065ae487b05074be">flow::net_flow::Congestion_control_classic::on_loss_event</a></div><div class="ttdeci">void on_loss_event(size_t bytes, size_t packets) override</div><div class="ttdoc">Implements Congestion_control_strategy::on_loss_event() API.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__classic_8cpp_source.html#l00046">cong_ctl_classic.cpp:46</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__strategy_html"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__strategy.html">flow::net_flow::Congestion_control_strategy</a></div><div class="ttdoc">The abstract interface for a per-socket module that determines the socket's congestion control behavi...</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl_8hpp_source.html#l00176">cong_ctl.hpp:180</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Shared__ptr__alias__holder_html_aef7998db71c60eeb5d1e3d1a97c14886"><div class="ttname"><a href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">flow::util::Shared_ptr_alias_holder&lt; boost::shared_ptr&lt; Peer_socket &gt; &gt;::Const_ptr</a></div><div class="ttdeci">Const_target_ptr Const_ptr</div><div class="ttdoc">Short-hand for ref-counted pointer to immutable values of type Target_type::element_type (a-la T cons...</div><div class="ttdef"><b>Definition:</b> <a href="shared__ptr__alias__holder_8hpp_source.html#l00127">shared_ptr_alias_holder.hpp:127</a></div></div>
<div class="ttc" id="acong__ctl_8hpp_html"><div class="ttname"><a href="cong__ctl_8hpp.html">cong_ctl.hpp</a></div></div>
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<div class="ttc" id="adetail_2net__flow__fwd_8hpp_html"><div class="ttname"><a href="detail_2net__flow__fwd_8hpp.html">net_flow_fwd.hpp</a></div></div>
<div class="ttc" id="anamespaceflow_1_1net__flow_html"><div class="ttname"><a href="namespaceflow_1_1net__flow.html">flow::net_flow</a></div><div class="ttdoc">Flow module containing the API and implementation of the Flow network protocol, a TCP-inspired stream...</div><div class="ttdef"><b>Definition:</b> <a href="asio_2node_8cpp_source.html#l00024">node.cpp:25</a></div></div>
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